OFFSET
2,1
LINKS
Nico Van Cleemput, Table of n, a(n) for n = 2..75
Gunnar Brinkmann and Nico Van Cleemput, Classification and generation of nanocones, Discrete Applied Mathematics, 159 (2011), 1528-1539.
FORMULA
Conjectured g.f.: x^2*(-2*x^8 + 5*x^7 + x^6 + 13*x^5 + 8*x^4 + 13*x^3 + 9*x^2 + 3*x + 2)/(x^12 - 3*x^11 + 2*x^10 + x^9 - x^8 + 2*x^7 - 4*x^6 + 2*x^5 - x^4 + x^3 + 2*x^2 - 3*x + 1). [D. S. McNeil, Oct 20 2011]
CROSSREFS
KEYWORD
nonn
AUTHOR
Nico Van Cleemput, Oct 20 2011
STATUS
approved